(2R)-4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl)butan-2-amine
Absorption
Sitagliptin is rapidly absorbed, with 100 mg reaching a C max of 950 nM in 1 to 4 h. The bioavailability is approximately 87%.
Distribution
Vd is approximately 198 L. Plasma protein binding is 38%.
Metabolism
Metabolism by CYP3A4 and, to a lesser degree, CYP2C8 is a minor pathway in the Cl of sitagliptin.
Elimination
Terminal t ½ is approximately 12.4 h. Approximately 13% is excreted in feces and 87% in urine via active tubular secretion (79% as unchanged drug). Sitagliptin is a substrate for organic anion transport.
Cyclosporine
Sitagliptin plasma concentrations may be increased modestly (approximately 68%), which is not expected to be clinically important.
Digoxin
Digoxin plasma levels may be increased slightly (approximately 18%); no dosage adjustment is recommended.
2.透過腎臟排出體外，對中度和重度腎功能不全患者須降低劑量。
使用條件：(105/5/1、114/6/1)
(1)原則上第二型糖尿病治療應優先使用metformin，或考慮早期開始使用胰島素。除有過敏、禁忌症、不能耐受或仍無法理想控制血糖的情形下，可使用其他類口服降血糖藥物。
(2) TZD製劑、DPP-4抑制劑、SGLT-2抑制劑、以及含該3類成分之複方製劑，限用於已接受過最大耐受劑量的metformin仍無法理想控制血糖之第二型糖尿病病人，且SGLT-2抑制劑與DPP-4抑制劑及其複方製劑宜二種擇一種使用。
(3)第二型糖尿病病人倘於使用三種口服降血糖藥物治療仍無法理想控制血糖者，宜考慮給予胰島素治療。
(4)特約醫療院所應加強衛教第二型糖尿病病人，鼓勵健康生活型態的飲食和運動，如控制肥胖、限制熱量攝取等措施。
